Emissive image display apparatus

ABSTRACT

A large screen emissive display operating at atmospheric pressure includes pixels, the red, green, and blue subpixels of which are excited by UV laser light scanned onto the subpixels by a pixel activation mechanism. The pixel activation mechanism includes three grating light valves (GLVs) that are controlled by a processor in response to a demanded image to modulate the UV light as appropriate to produce the demanded image.

FIELD OF THE INVENTION

[0001] The present invention relates generally to image displays.

BACKGROUND OF THE INVENTION

[0002] Image displays include emissive displays, such as phosphordisplays used in cathode tube-based television and computer monitors,and transmissive displays, such as projection displays used for largescreen TVs. An emissive display works by emitting visible light frompixels that are excited by, e.g., electron beams or fluorescent lamps.In the case of conventional electron beam-based displays, the electronbeam is scanned across the pixels as appropriate to excite the pixels toproduce a demanded image. In the case of fluorescent lamp-based displayssuch as plasma displays, ultraviolet light from a gas discharge isdirected to appropriate pixels that are physically shielded from eachother, with the pixel illumination pattern necessary to produce thedemanded image not being established by scanning the UV light, which issimply a discharge from the lamp, but by appropriately blocking the UVlight to impinge only on the desired pixels. Both of the above-mentionedemissive displays require the presence of a vacuum within the device,which can complicate manufacturing and raise costs.

[0003] Because the weight of some emissive displays becomes infeasiblylarge in the case of large screen displays, e.g., displays having sizesof 40″-60″ or more, the above-mentioned transmissive displays have beenprovided, an example of which is the projection display. A projectiondisplay works by projecting pixellated light from a relatively smallsource onto a relatively large projector, which “transmits” the lighttoward the viewers.

[0004] As recognized herein, while effective, large screenprojection-type displays suffer from the drawback of relatively lowimage quality, compared to the image quality afforded by a smalleremissive display. On the other hand, current emissive displaytechnology, as noted above, cannot easily be used to establish largescreen displays owing to weight and other practical restrictions.

[0005] Nevertheless, the present invention recognizes that it would bedesirable to provide a large screen emissive display to overcome theimage quality drawback of many large transmissive displays.

SUMMARY OF THE INVENTION

[0006] An image display apparatus includes an emissive display that hasplural pixels. A source of ultraviolet (UV) light directs UV light to apixel activation mechanism, which scans the UV light onto the pixels inresponse to a demanded image.

[0007] In a preferred embodiment, the display is a large screen display,and the light source is a UV laser. The display can be a phosphordisplay, and it can operate at atmospheric pressure. Or, the display canbe a liquid crystal display.

[0008] In any case, the preferred pixel activation mechanism can includea grating light valve (GLV) that is controllable by a processor toestablish a demanded image. In a particularly preferred embodiment,three GLVs are controlled by the processor to establish the demandedimage. To render three beams, one for each GLV, a beamsplitter receivesUV light from the laser and directs respective UV beams to the GLVs. Afirst GLV is controlled to direct UV light onto only blue subpixels ofthe display, a second GLV is controlled to direct UV light onto only redsubpixels of the display, and a third GLV is controlled to direct UVlight onto only green subpixels of the display.

[0009] In the preferred embodiment discussed further below, scanningmirrors are associated with respective GLVs, with each mirror beingoscillated about a respective axis, to produce a two-dimensional scanfrom the one-dimensional modulation afforded by the GLVs. Additionally,a mask that has excitation light apertures defining respective pitchescan be interposed between the GLVs and the display. If desired, thepitches between the excitation light apertures are established based onthe locations of the respective excitation light apertures relative tothe display.

[0010] If desired, the display can include a substrate on which pixelsare established. Each pixel is established by respective red, green, andblue subpixels. A light refracting layer can cover the pixels. In thisembodiment, the pixel activation mechanism directs first, second, andthird UV beams against the refracting layer at respective first, second,and third angles, whereby the first, second, and third beams arerefracted by the refracting layer only onto respective red, green, andblue subpixels. To ensure color purity, a variable pitch color selectionmask layer can be juxtaposed with the refracting layer for shielding theblue and green subpixels from the first beam, shielding the red andgreen subpixels from the second beam, and shielding the red and bluesubpixels from the third beam.

[0011] In another aspect, a method for producing a demanded imageincludes receiving the demanded image, and directing light onto adisplay using plural light valves. The light valves are controlled inaccordance with the demanded image.

[0012] In still another aspect, a video display apparatus is disclosedfor presenting a demanded image. The apparatus includes a phosphordisplay operating at atmospheric pressure, a UV laser beam source, andfirst, second, and third grating light valves (GLVs) directingrespective first, second, and third beams from the laser beam sourceonto the display to activate respective red, blue, and green subpixelsof the display. A processor operably controls the GLVs in accordancewith the demanded image.

[0013] The details of the present invention, both as to its structureand operation, can best be understood in reference to the accompanyingdrawings, in which like reference numerals refer to like parts, and inwhich:

BRIEF DESCRIPTION OF THE DRAWINGS

[0014]FIG. 1 is a schematic diagram of the present emissive display,using a phosphor screen;

[0015]FIG. 2 is a schematic diagram of the variable pitch mask; and

[0016]FIG. 3 is a schematic diagram of an alternate phosphor screenassembly.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0017] Referring initially to FIG. 1, a display apparatus is shown,generally designated 10, which includes an emissive display 12 thatdefines plural pixels, each pixel in turn being defined by threesubpixels in accordance with emissive display principles known in theart, namely, red, green, and blue subpixels. In the non-limitingillustrative embodiment shown in FIG. 1, the display 12 is a largescreen phosphor display, the pixels of which may be composed of, e.g.,Zinc Sulfide. By “large screen” is meant that the operational “D” of thedisplay 12 is at least forty inches (40″) (about one hundredcentimeters) and can be sixty inches (60″) (about one hundred fiftycentimeters) or more. The principles advanced herein, however, can beapplied to smaller displays, as well as to other emissive displays, suchas plasma displays. In any case, owing to the structure disclosed below,the display 12 operates at atmospheric pressure, i.e., the display 12does not require a vacuum in which to operate.

[0018] As can be appreciated in reference to FIG. 1, the display 12 isirradiated by plural moving light beams 14. In the preferred embodiment,first through third beams 14 are used. As disclosed further below, afirst one of the beams 14 can irradiate only red subpixels, a second oneof the beams 14 can irradiate only green subpixels, and a third one ofthe beams 14 can irradiate only blue subpixels. In the presentlypreferred embodiment, the beams 14 are ultraviolet (UV) beams and morepreferably are UV laser beams that originate at a laser 16.

[0019] Explaining FIG. 1 from the laser 16, a source beam 18 is emittedby the laser 16 that is split into the three beams 14 by a beamsplitter20 device. The beamsplitter device 20 can include two beamsplitters, oneof which splits the source beam 18 in two and another of which splitsone of the resulting two beams into two beams, to establish thepreferred three beam arrangement shown.

[0020] The three beams 14 then propagate toward respective light valves22. In the preferred embodiment, the light valves 22 are grating lightvalves (GLVs). In non-limiting examples, the GLVs may be those disclosedin U.S. Pat. No. 5,311,360, incorporated herein by reference, or in[insert Sony patents here].

[0021] Accordingly, the light valves 22 reflect their respective beams14 in accordance with light valve principles known in the art.Specifically, each light valve 22 can include a one-dimensional row ofmovable mirrors which can reflect light. In a particularly preferred,non-limiting embodiment, six adjacent mirrors per subpixel are used. Aprocessor 24 is operably engaged with the light valves 22 to cause eachvalve 22 to modulate its respective beam 14 in accordance with ademanded image received from, e.g., a television tuner, a computer, orother video source. That is, the mirrors of the light valves 22 aremoved as appropriate to reflect or not the respective beam 14, tothereby establish the position of the beam 14 in the dimension definedby the light valves 22 for any given frame of the demanded image.

[0022] Thus, the beams 14 are essentially scanned in one dimension inaccordance with the demanded image. To achieve the requisitetwo-dimensional scan, each beam 14 propagates from its respective lightvalve 22 to a respective scanning mirror 26, each of which oscillatesabout its axis as driven by a respective motor 28 in a dimension that isorthogonal to the dimension of the light valves 22. The scanning mirrors26 need not be controlled in accordance with the demanded image; rather,only the light valves 22 need be controlled to produce the demandedimage, with the processor 24 taking account of the orthogonal scanningof the beams 14 provided by the scanning mirrors 26.

[0023] If desired, a mask 30 can be interposed between the scanningmirrors 26 and the display 12 to establish a light barrier betweenadjacent pixels. The mask 30 defines a two-dimensional grid ofdifferently-sized excitation light apertures 32. The mask 30 can includean opaque substrate and the apertures 32 can be established by openingsin the substrate. Alternatively, the mask 30 can include a transparentsubstrate and the apertures can be established by ink-jet printing anopaque pattern on the substrate, with non-printed portions of thesubstrate establishing the apertures.

[0024] As best shown in FIG. 2, the sizes of the excitation lightapertures 32 and/or pitch (that is, the spacing between adjacentexcitation light apertures 32) are established based on the locations ofthe respective excitation light apertures 32 relative to the display 12.Specifically, to allow for uniform radiation intensity of pixels nearthe center of the display 12 and pixels near the edges of the display12, the size and/or pitch of the excitation light apertures 32 canchange from the center of the display 12 outward. Accordingly, in onenon-limiting embodiment the sizes of the excitation light apertures 32and/or the spacing between excitation light apertures 32 that are nearthe center of the display 12 can be smaller than the sizes of theexcitation light apertures 32 and/or the spacing between excitationlight apertures 32 that are nearer the edges of the display 12. Theparticular excitation light aperture size/pitch variation is establishedbased on the geometry of the system 10.

[0025]FIG. 3 shows an alternate display, generally designated 40, whichincludes a transparent, e.g., glass, substrate 42 and plural red, green,and blue subpixels 44 that are established on the substrate 42. It is tobe understood that three adjacent subpixels establish a pixel. Atransparent light refracting layer 46 covers the pixels and is opposedto the substrate 42 as shown. If desired, the layer 46 can be made ofplural sublayers, i.e., a first sublayer for refracting a beam that isto excite only red subpixels, a second sublayer for refracting a beamthat is to excite only green subpixels, and a third sublayer forrefracting a beam that is to excite only blue subpixels.

[0026] In any case, as shown in FIG. 3, the UV beams 14 are directedagainst the refracting layer 46. The location and configuration of thelight valves 22 relative to the display 12 and the light valve controlafforded by the processor 24 ensures that the light valve 22 that is toreflect the beam for exciting only red subpixels reflects the beam at aset of angles α with respect to the plane of the light refracting layer46, the light valve 22 that is to reflect the beam for exciting onlygreen subpixels reflects the beam at a set of angles β, and the lightvalve 22 that is to reflect the beam for exciting only blue subpixelsreflects the beam at a set of angles γ, with the angles α, β, and γ forany one pixel being different from each other. Consequently, the threebeams are refracted at differing angles by the refracting layer 46 onlyonto respective red, green, and blue subpixels 44.

[0027] To ensure that the three beams impinge on only their intendedsubpixels, a color selection mask layer 48 can be juxtaposed with therefracting layer 46 for shielding the blue and green subpixels from thefirst beam, shielding the red and green subpixels from the second beam,and shielding the red and blue subpixels from the third beam. The colorselection mask layer 48 can be deposited onto the refracting later 46 asone or more thin films by, e.g., ink jet printing the film onto therefracting layer 46. Like the mask 30 shown in FIG. 1, the colorselection mask layer 48 can define apertures 50 that have a variablepitch and/or variable size, based on the positions of the apertures 50relative to the center of the substrate 42.

[0028] While the particular EMISSIVE IMAGE DISPLAY APPARATUS as hereinshown and described in detail is fully capable of attaining theabove-described objects of the invention, it is to be understood that itis the presently preferred embodiment of the present invention and isthus representative of the subject matter which is broadly contemplatedby the present invention, that the scope of the present invention fullyencompasses other embodiments which may become obvious to those skilledin the art, and that the scope of the present invention is accordinglyto be limited by nothing other than the appended claims, in whichreference to an element in the singular is not intended to mean “one andonly one” unless explicitly so stated, but rather “one or more”. Allstructural and functional equivalents to the elements of theabove-described preferred embodiment that are known or later come to beknown to those of ordinary skill in the art are expressly incorporatedherein by reference and are intended to be encompassed by the presentclaims. Moreover, it is not necessary for a device or method to addresseach and every problem sought to be solved by the present invention, forit to be encompassed by the present claims. Furthermore, no element,component, or method step in the present disclosure is intended to bededicated to the public regardless of whether the element, component, ormethod step is explicitly recited in the claims. No claim element hereinis to be construed under the provisions of 35 U.S.C. §112, sixthparagraph, unless the element is expressly recited using the phrase“means for” or, in the case of a method claim, the element is recited asa “step” instead of an “act”.

What is claimed is:
 1. An image display apparatus, comprising: anemissive display having plural pixels; at least one source ofultraviolet (UV) light; and a pixel activation mechanism scanning the UVlight onto the pixels in response to a demanded image.
 2. The apparatusof claim 1, wherein the display is a large screen display.
 3. Theapparatus of claim 1, wherein the display is a phosphor display.
 4. Theapparatus of claim 3, wherein the phosphor display operates atatmospheric pressure.
 5. The apparatus of claim 1, wherein the displayis a liquid crystal display.
 6. The apparatus of claim 1, wherein thepixel activation mechanism includes at least one grating light valve(GLV) controllable by a processor to establish a demanded image.
 7. Theapparatus of claim 6, comprising plural GLVs controllable by a processorto establish the demanded image.
 8. The apparatus of claim 7, comprisingat least one beamsplitter receiving UV light from the source anddirecting respective UV beams to the GLVs.
 9. The apparatus of claim 7,comprising plural scanning mirrors, each mirror being associated with arespective GLV, each mirror being oscillated about a respective axis.10. The apparatus of claim 9, comprising three and only three GLVs, afirst GLV being controlled to direct UV light onto only blue subpixelsof the display, a second GLV being controlled to direct UV light ontoonly red subpixels of the display, and a third GLV being controlled todirect UV light onto only green subpixels of the display.
 11. Theapparatus of claim 7, further comprising at least one mask having pluralexcitation light apertures defining respective pitches, the mask beinginterposed between the GLVs and the display, the pitches between theexcitation light apertures being established based on the locations ofthe respective excitation light apertures relative to the display. 12.The apparatus of claim 1, wherein the source is a laser.
 13. Theapparatus of claim 1, wherein the display includes at least onesubstrate, plural pixels being established on the substrate, each pixelbeing established by respective red, green, and blue subpixels, at leastone light refracting layer covering the pixels and opposed to thesubstrate.
 14. The apparatus of claim 13, wherein the pixel activationmechanism directs first, second, and third UV beams against therefracting layer at respective first, second, and third angles, wherebythe first, second, and third beams are refracted by the refracting layeronly onto respective red, green, and blue subpixels.
 15. The apparatusof claim 14, further comprising a color selection mask layer juxtaposedwith the refracting layer for shielding the blue and green subpixelsfrom the first beam, shielding the red and green subpixels from thesecond beam, and shielding the red and blue subpixels from the thirdbeam.
 16. A method for producing a demanded image, comprising: receivingthe demanded image; and directing light onto a display using plurallight valves, the light valves being controlled in accordance with thedemanded image.
 17. The method of claim 16, wherein the light valves aregrating light valves (GLVs), and the light is UV light.
 18. The methodof claim 17, wherein the act of directing includes modulating the UVlight using the GLVs in accordance with the demanded image.
 19. Themethod of claim 18, further comprising interposing oscillating scanningmirrors between the GLVs and the display.
 20. The method of claim 18,wherein the display is a large screen display.
 21. The method of claim20, wherein the display is a phosphor display.
 22. The method of claim21, comprising operating the phosphor display at atmospheric pressure.23. The method of claim 20, wherein the display is a liquid crystaldisplay.
 24. The method of claim 18, comprising: generating a single UVlight beam using a laser; and splitting the single UV light beam intothree light beams impinging on respective GLVs.
 25. The method of claim24, comprising: directing a first light beam only onto red subpixels inthe display; directing a second light beam only onto green subpixels inthe display; and directing a third light beam only onto blue subpixelsin the display.
 26. The method of claim 7, further comprisinginterposing between the GLVs and the display at least one mask havingplural excitation light apertures defining respective pitches, thepitches between the excitation light apertures being established basedon the locations of the respective excitation light apertures relativeto the display.
 27. A video display apparatus for presenting a demandedimage, comprising: a phosphor display operating at atmospheric pressure;at least one UV laser beam source; at least first, second, and thirdgrating light valves (GLVs) directing respective first, second, andthird beams from the laser beam source onto the display to activaterespective red, blue, and green subpixels of the display; and at leastone processor operably controlling the GLVs in accordance with thedemanded image.
 28. The apparatus of claim 27, wherein the display is alarge screen display.
 29. The apparatus of claim 28, wherein the displayhas at least one operational dimension of at least forty inches (40″).30. The apparatus of claim 28, wherein the display has at least oneoperational dimension of at least fifty inches (50″).
 31. The apparatusof claim 28, wherein the display has at least one operational dimensionof at least sixty inches (60″).
 32. The apparatus of claim 27,comprising at least one beamsplitter receiving UV light from the sourceand directing respective UV beams to the GLVs.
 33. The apparatus ofclaim 27, comprising plural scanning mirrors, each mirror beingassociated with a respective GLV, each mirror being oscillated about arespective axis.
 34. The apparatus of claim 27, further comprising atleast one mask having plural excitation light apertures definingrespective pitches, the mask being interposed between the GLVs and thedisplay, the pitches between the excitation light apertures beingestablished based on the locations of the respective excitation lightapertures relative to the display.
 35. The apparatus of claim 27,wherein the display includes at least one substrate, plural pixels beingestablished on the substrate, each pixel being established by respectivered, green, and blue subpixels, at least one light refracting layercovering the pixels and opposed to the substrate.
 36. The apparatus ofclaim 35, wherein the first, second, and third beams impinge against therefracting layer at respective first, second, and third angles, wherebythe first, second, and third beams are refracted by the refracting layeronly onto respective red, green, and blue subpixels.
 37. The apparatusof claim 36, further comprising a color selection mask layer juxtaposedwith the refracting layer for shielding the blue and green subpixelsfrom the first beam, shielding the red and green subpixels from thesecond beam, and shielding the red and blue subpixels from the thirdbeam.
 38. An image display apparatus, comprising: display means havingplural pixels; at least one source of ultraviolet (UV) light; and pixelactivation means scanning the UV light onto the pixels in response to ademanded image.